In deep submicron integrated circuits, process variation can be very significant. The same circuit can be “fast” in one wafer and “slow” in another. Even within the same wafer, it can be fast in one die but slower in the other. The speed of the circuit is also dependent on the supply voltage level as well as temperature but to a lesser extent. In general, circuits speed up when supply voltage is raised and slow down when supply voltage is lowered.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present invention.